Airplanes, helicopters, rockets, satellites, ships, tanks, autonomous ground vehicles and other sophisticated machines-in-motion utilize complex guidance, control and other mission-critical electronics. In such systems, it is imperative that all of the components and their interconnecting pieces function reliably. It is known that electrical interconnections between components degrade and can malfunction over time. Degradation curves of electromechanical components suggest that intermittence, a state where a circuit experiences brief fluctuations in resistance will be the most likely failure mode first encountered. Constant failures in these systems are relatively easy to diagnose and repair.
Intermittent failures in these systems, however, are extremely difficult to detect, isolate and resolve. Traditional attempts to detect intermittent failures are generally performed using serial test methods which measure ohmic continuity, one circuit at a time, even when thousands of circuits are involved. The technologies typically employed such as Automatic Wire Testers (AWTs), Digital Multimeters (DMMs) and even Time Domain Reflectometry (TDR)) are fundamentally ineffective for detecting randomly occurring, low-level, intermittent faults. These technologies are designed to provide stable readings from a constantly failing circuit, and notably, all these continuity-type test technologies serially scan and/or test only one line or circuit at a time.
Conversely, intermittence by its very definition occurs randomly in time, duration and amplitude. In a complex system consisting of multiple circuits, the odds of an elusive intermittent failure occurring at the exact moment a serial scanning technology is actively measuring the failing circuit is infinitesimally small. While oscilloscopes are generally able to detect intermittence, their trigger can only be engaged on a single line or circuit at time so they too fail to perform when testing a multitude of circuits. Oscilloscopes also require an electrical stimulus on the line, making them largely impractical and unsuitable for testing hundreds or thousands of circuits and connection points.